This invention relates to an elongated, nonconductive flexible rod commonly used by electricians and telephone or communications installers and technicians, and referred to in the art as xe2x80x9cfishtapexe2x80x9d. Fishtape is typically used to facilitate installation of wire and cable through conduit or other passageway in walls, ceilings, and floors of buildings. Standard fishtapes are made of 0.080xe2x80x3 to 0.500xe2x80x3 diameter fiberglass or extruded plastic, and are supplied in reels containing 50 or more feet of tape.
Because most electrical wire and cable is relatively thin and flexible, pushing it through long lengths of conduit is virtually impossible. To facilitate running wire and cable using fishtape, a length of fishtape is first fed through the conduit from one open end to the other. The wire or cable is then attached to a leading end of the fishtape, and the fishtape pulled back through the conduit with the attached wire or cable trailing behind. During this process, substantial friction resistance is often encountered between the surfaces of the fishtape, wires or cables, and the walls of the conduit or passageway through which the wires or cables are being pulled. Overcoming this resistance generally requires considerable pulling force. To be effective, a fishtape must be stiff enough to be pushed through conduit, flexible enough to negotiate bends or turns in the conduit, and strong enough to pull multiple wires or cables back through the conduit, overcoming the friction resistance without breaking or separating from the wires or cables being pulled.
Therefore, it is an object of the invention to provide a fishtape which provides enhanced fishability through conduit and other passageways in walls and floors of buildings.
It is another object of the invention to provide a fishtape which is sufficiently flexible to negotiate bends and turns in a conduit or passageway.
It is another object of the invention to provide a fishtape which has relatively high tensile strength.
It is another object of the invention to provide a fishtape which resists kinking.
It is another object of the invention to provide a fishtape which can be easily gripped.
It is another object of the invention to provide a fishtape which yields less friction resistance when pushed or pulled through a conduit or passageway.
It is another object of the invention to provide a fishtape which can be used to obtain an approximation of the location of an obstruction in a conduit or passageway.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a fishtape adapted for being fed through an internal passageway of a structure, such as a commercial or residential building. The fishtape includes an elongated, flexible rod with a plurality of circumferentially-spaced, longitudinal ribs. The ribs are adapted to promote the fishability of the fishtape through the internal passageway of the structure.
According to another preferred embodiment of the invention, the flexible rod has a fiberglass or extruded plastic core.
According to another preferred embodiment of the invention, the diameter of the fiberglass or extruded plastic core is less than one-half the diameter of the flexible rod.
According to another preferred embodiment of the invention, the flexible rod has an exterior sheath.
According to another preferred embodiment of the invention, the exterior sheath is formed of nylon.
According to another preferred embodiment of the invention, each of the longitudinal ribs has a point and first and second grooves formed on opposite sides of the point.
According to another preferred embodiment of the invention, the distance between a top of the point and a bottom of either groove is approximately 0.01 inches.
According to another preferred embodiment of the invention, a top of the point and a bottom of each groove define substantially equal radii.
According to another preferred embodiment of the invention, a top of the point of each rib defines a radius of approximately 0.005 inches.
According to another preferred embodiment of the invention, a bottom of each groove defines a radius of approximately 0.005 inches.
According to another preferred embodiment of the invention, the angular distance between grooves of each rib measured from a center of the fiberglass rod is between 15 and 20 degrees.